deep_stage_srt4

i wrote this for an English class, so if things seem over simplified, they are. but its still a good read. enjoy!

NEED FOR SPEED
(Evaluating how much speed you really need.)

There are many ways automobiles can be made more efficient. Many times simple things like, air filters with high flow filter elements, or low restriction exhaust systems can dramatically improve an automobiles response. The reason such simple changes can cause significant increases in performance is because they improve on the driving force of an engine, combustion. Combustion in a motor, is the point when an air and fuel mixture is compressed and then ignited, causing expansion, which is a cycle the engine continues. Increasing efficiency of an engines ability to perform this function is translated into an increase in power. A larger diameter exhaust system with a low-restriction muffler allows the engine to move spent gasses away from the motor more efficiently. The more exhaust gas that is pushed out of the cylinder will create more vacuum to pull fresh air and fuel in for combustion. Through an engine’s natural aspiration air must be pulled into the engine by vacuum, which draws away from the motor’s ability to produce power. High-flow filters and even full cold air intake systems allow more air into the cylinders more quickly, but there is technology that can almost eliminate the need for power-robbing vacuum compression. Focusing on induction, there are three ways an engine can be made more powerful. Each alteration of induction is different, but all work on the principle of more air in equals more power. Stroking, supercharging, or turbocharging an engine are the three best ways’s to increase induction efficiency and the motor’s ability to produce power. Skill level, power desired, and budget amount should all be taken into consideration before beginning such a project.

In each cylinder of a motor is a piston; under each piston is a connecting rod, which gets its name from its job, connecting the piston to a steel bar full of alternating offsets (journals) called the crankshaft. An Engine’s stroke is the measurement of the total distance a piston moves up and down within the cylinder walls. This measurement is important because it directly effects how much power an engine can make. On the piston’s down-stroke, a certain volume of air and fuel is pulled into the cylinder. During the pistons upstroke, compression is created just before the spark plug ignites the mixture; causing expansion and pushing the piston back down. This cycle continues among all cylinders and causes the crankshaft to spin, which spins the transmission and finally puts power to the ground. To “Stroke” an engine means to alter internal engine parts in order to increase an engines cylinder volume, which would increase the amount of ignited air and fuel. Stroking is achieved by; shortening the connecting rods, altering the journals on the crank shaft or lowering the profile of a piston. The process is very demanding of time and automotive technical skills, but the parts are often available in many different kits and can be installed with little alteration to any other elements in the engine bay. The process can become very expensive with the addition of machine work done to the block and head of the engine. Engine stroking is cheaper with engine types like the Chevy 350ci, Ford 302ci, or Dodge 440ci because of their popularity. Kits usually cost less then one thousand dollars and will require much preparation. Stroking an engine can dramatically increase power output but not without a lot of time, and money. Finding an engine builder capable of the machine work is something that must be done before the project. Stroking is a good way to build power, strengthen an engine and still maintain the possibility of adding forced induction.

Engineers since the twenties have been using belt-driven induction to power piston engine planes and automobiles. This type of induction system has undergone many changes since its creation and is now referred to as supercharging. A Supercharger is an external, bolt-on type application that forces a pressurized air/fuel mixture into the cylinders of an engine. It replaces the intake manifold and utilizes the engines under-drive pulley to spin a turbine that creates positive pressurized air. Positive pressure means that the engine is never in vacuum and air is constantly forced into the engine (forced induction). The amount of pressure the supercharger makes is measured in pounds-per-square inch (PSI) and is usually relatively low throughout all RPM (revolutions per minute) ranges. Because the supercharger is belt-driven from the under drive pulley on the front of the engine, it takes power from the engine to power itself. For example: if 10psi of boost is achieved which translates into 20 horsepower gained, and the supercharger takes 5 horsepower to turn it’s turbine, only 15 horsepower would actually be gained. Supercharger applications can range from four cylinder daily-drivers all the way up to professional drag racing cars, and are often sold in kits. Large, top-mounted superchargers may interfere with hood clearance and require the removal of portions of the car hood above the motor. Installing a supercharger is not very demanding on time or budgets, also, much less skill is needed to install or tune the system.
The superchargers popularity comes from its good power-to-price ratio and that it needs only a small amount of supporting hardware to run. Supercharger kit prices can range from $700 and up depending on size and options.


Anybody who loves to go fast loves free horsepower. This is the reason turbocharging reigns supreme among the power-multipliers. Turbochargers or simply turbos have the ability to deliver the massive power of a stroker kit but with much less difficulty and none of the power-robbing effects of the supercharger. Turbos generally consist of two housing bolted next to each other, resembling a snail. In each house are wheels that resemble small fans. The impeller is the small fan that is spun by exhaust gasses leaving the combustion chamber and is fixed to the other turbine wheel by a small rod running through the center of the housings. When the spent exhaust gasses pass through the impeller on their way to the tailpipe they spin the fins on the impeller wheel. The impeller spins the turbine wheel in the other housing, which creates a vacuum and pulls air into the turbine housing, down thorough additional piping and into the intake manifold. Turbochargers utilize already used exhaust gasses and require no additional power from the engine, hence the term free-horsepower. Turbos are not necessarily the “perfect weapon” to have under the hood, they have their flaws also. Turbochargers can boost 30psi and higher( if 14.7psi is atmospheric pressure 30psi is like adding two more atmospheres of pressure into the intake.), however this can cause the turbine housing to spin in access of 100,000 RPM’s which creates and enormous amount of heat. Turbos can melt plastic parts and even weak metal welds that are in close proximity to it. Engines often have trouble complying with the high compression created by high volumes of compressed air and fuel. In most situations, connecting rods and low compression pistons must be used. Due to the turbochargers power making process, there is a lot of additional hardware needed to run it successfully. Along with the turbo, an intercooler to cool hot intake air, larger fuel injectors, waste gates that expel excessive intake charge and engine management systems are often required to run a turbo set-up. Turbo kits usually come with all the supporting hardware and cost around $5,000. Most of the work can be done by a person will little automotive knowledge but has the ability to follow directions closely. Some welding might be required that can be done by any trusted mechanic. Turbo instillation can be accomplished timely but tuning boost (psi) levels takes a lot of time and patience.

With great power comes great responsibility. Stroker kits are very low maintenance once installed, while superchargers and turbochargers can be very demanding on an engine. When high performance is expected, high maintenance becomes a necessity. Internal combustion engines involve many separate functions synergized to create horsepower. Elements in the motor have very little tolerance for error and should be closely evaluated to prevent premature engine failure. Engine oil cannot go unchecked; belts and pulleys must constantly be inspected and even tires need to be checked for correct tire pressure and performance coding. It is important to remember that a project budget should involve more then increasing engine power. Upgrades to the breaks, suspension, and transmission should be considered to increase longevity and drivability of the vehicle. All options consist of pros and cons, research and evaluate which ever application is chosen with the vehicle it will be applied to. Any of the three options can increase efficiency, power and actually improve gas mileage, though the effects are often counteracted by the temptation of speed. Regardless of how automotive power is obtained remember, on the street, people will respect a mean car, but not a mean driver.

__________________
There is no replacement for displacement, like a turbo! -dssrt4

**Sponsored By **

86_Notch

very well written you've got a sure fire A ++ for mentioning the ford 302 altho i must deduct points for not mentioning the king of all poweradders ........NITROUS !!!!!

__________________
__________________________
|.....Overnight.........................| ||
|........Parts From Japan.............||'|";,___
|_..._...____________======||_|_|...,..]
"(@)'(@)''''''''''''''''''''''''*|(@)(@)*****" (@)

95GST

Well worded, If you don't an A give your teacher my number. Very nice write up and well explained.

__________________
Boost. My anti-drug

deep_stage_srt4

thanks guys! word count restrictions prevented a section on nitrous notch! i can post up some more essays i've written, though most dont have anything to do with cars

__________________
There is no replacement for displacement, like a turbo! -dssrt4

**Sponsored By **